A silicon-on-insulator substrate is disclosed which comprises: a silicon substrate layer; a first insulation layer over the silicon substrate layer; a conductive layer over the first insulation layer comprising at least one metal or metal silicide over the first insulation layer; a second insulation layer over the conductive layer; a silicon device layer comprising silicon over the second insulation layer; and at least one conductive plug through the silicon substrate layer and the first insulation layer contacting the conductive layer, or at least one conductive plug through the silicon device layer and the second insulation layer contacting the conductive layer. Also disclosed are methods for making silicon-on-insulator substrates having improved heat transfer structures.